The presidential election of 2016 is still two years away, but already the claws are coming out in the race to become the Republican candidate.

In an op-ed titled “Rick Perry Is Dead Wrong,” Sen. Rand Paul took to Politico today to criticize the governor of Texas. Paul’s attack comes in response to an op-ed penned by Perry for The Washington Post last week in which Perry wrote Paul’s “isolationist policies would...endanger our national security.” As it stands, Perry is not a credible threat to Paul for the 2016 GOP Presidential nomination. Paul leads Perry by almost 10 points in most polls.

“There are many things I like about Texas Gov. Rick Perry, including his stance on the Tenth Amendment to the Constitution,” Sen. Paul wrote. “But apparently his new glasses haven’t altered his perception of the world, or allowed him to see it any more clearly.”

Sen. Paul started off with a quick jab at Perry’s handling of the immigration crisis. “[W]ith 60,000 foreign children streaming across the Texas border, I am surprised Governor Perry has apparently still found time to mischaracterize and attack my foreign policy,” Paul wrote.

The Senator followed it up by comparing Perry to President Barack Obama on the issue of Iraq, emphasizing that, during a 2012 Republican presidential primary debate, Perry said he would support sending troops back into Iraq—an unpopular position with voters.

The conflict between Paul and Perry mirrors the larger conflict within the GOP between fiscal doves and neoconservative hawks. Doves like Paul want smaller deficits and less involvement abroad. Hawks like Perry want ample US power projection and a hardline stance on terror.

What voters want remains to be seen, but most polls have Paul leading the field—just—beating Governors Jeb Bush, Mike Huckabee and Chris Christie, his three closest Republican primary rivals, by one point in the most recent poll.